Downtown 300i Rear Axle Size?

[Seanny]

Hi all,

I was attempting to do a rear wheel removal and I am at the point of removing the rear axle nut but don't have the correct nut size socket.

At first I was looking at this website: https://www.oemmotorparts.com/oem5.asp?M=kymco&T=DOWNTOWN%20300%20I%20ABS&Y=_&L=KYMCO_Downtown%20300%20i%20ABS&O=Rear%20Wheel%20%20&F=KYMCO_Downtown%20300%20i%20ABS_Rear%20Wheel%20%20&L2=KYMCO_Downtown%20300%20i%20ABS_Rear%20Wheel

and at part 90305 it saids size 16mm, which is rather small but I thought thats correct. But when I actually get to that point where I am going to remove the nut its way bigger than a 16mm. I have a 21mm and it's barely not big enough and my biggest one is 32mm which I used for my previous bike and thats too big.

I think what they mean by 16mm is the thread size but the nut size is different?

Anyone know what size it is so that I can go buy it?

Thanks in advance!

Seanny

[mousejunks]

Nut size is 24mm, same as the oil filter cap. My 21mm and 23mm sockets do not fit at all and 25mm fits loosely.

[CROSSBOLT]

Hi all,

I was attempting to do a rear wheel removal and I am at the point of removing the rear axle nut but don't have the correct nut size socket.

At first I was looking at this website: https://www.oemmotorparts.com/oem5.asp?M=kymco&T=DOWNTOWN%20300%20I%20ABS&Y=_&L=KYMCO_Downtown%20300%20i%20ABS&O=Rear%20Wheel%20%20&F=KYMCO_Downtown%20300%20i%20ABS_Rear%20Wheel%20%20&L2=KYMCO_Downtown%20300%20i%20ABS_Rear%20Wheel

and at part 90305 it saids size 16mm, which is rather small but I thought thats correct. But when I actually get to that point where I am going to remove the nut its way bigger than a 16mm. I have a 21mm and it's barely not big enough and my biggest one is 32mm which I used for my previous bike and thats too big.

I think what they mean by 16mm is the thread size but the nut size is different?

Anyone know what size it is so that I can go buy it?

Thanks in advance!

Seanny

And 15/16ths fits the oil filter cap perfectly....

The books ALWAYS quote thread size!

[Seanny]

And 15/16ths fits the oil filter cap perfectly....

The books ALWAYS quote thread size!

Thank you both for the info, didn't know about the book's always quote thread size good to learn.

On a side note, when I was taking off the exhaust muffler case, I realize the nuts have washers and foams. Is it necessary to replace them and if so how do I replace the foam part? Its easy to find new washers but the foam I am not sure as someone that's not familiar with auto repair.

[CROSSBOLT]

Thank you both for the info, didn't know about the book's always quote thread size good to learn.

On a side note, when I was taking off the exhaust muffler case, I realize the nuts have washers and foams. Is it necessary to replace them and if so how do I replace the foam part? Its easy to find new washers but the foam I am not sure as someone that's not familiar with auto repair.

Even John Deere and Beechcraft manuals describe fasteners by threaded diameter rather than hex size. Seems to be an industry standard.

"Muffler case" the same thing as the plastic heat shield so we don't get burned on the hot muffler?

I am familiar with the heat shield held on with hex head bolts with heat resistant fiber washers. Is that what you are talking about? The "foam washers" have me stumped.

[Stig / Major Tom]

An exploded parts diagram of the exhaust will show the correct orientation of those fibre washers/screws for reinstall.
Online Kymco parts sellers all use the same exploded diagrams.
Stig

[Seanny]

Even John Deere and Beechcraft manuals describe fasteners by threaded diameter rather than hex size. Seems to be an industry standard.

"Muffler case" the same thing as the plastic heat shield so we don't get burned on the hot muffler?

I am familiar with the heat shield held on with hex head bolts with heat resistant fiber washers. Is that what you are talking about? The "foam washers" have me stumped.

They are two different parts, the washer is just a typical washer like this: https://static.grainger.com/rp/s/is/image/Grainger/53MF83_GC01?hei=1000&wid=1000
but then there's also a piece of small ring shape foam. So I was just wondering if I have to replace that as well when I assemble everything back.

Btw totally not in the industry just a dumb joe trying to fix my own scooter and save some money but at least I am trying. I can either at least give a try and learn or I can just give up and not do anything. Other than that I don't know what else to respond. I am not trained, I have not worked in the industry. I only do minimum maintenance and I read the manual, watch youtube videos, and search forums on how to do it. In this case, the manual doesn't have the nut socket size and I searched parts for size and it doesn't give that as well, so I have no choice but to ask other owners for info. If I can pay money to solve this I would love to so that I don't bother anyone here but the only Kymco dealer around my area shut down because of lack of business. Some motorcycle repair shops don't even touch a Kymco because they haven't fixed one before and don't want to be held liable if anything happens. Some others will fix it but they might have to figure things out step by step. Luckily I found a thread here that shared step by step details as well as video links that gave me confidence to do it so I thought I might give it a try. I don't know any industry standards forgive me if thats preposterous for some users here.

[Seanny]

An exploded parts diagram of the exhaust will show the correct orientation of those fibre washers/screws for reinstall.
Online Kymco parts sellers all use the same exploded diagrams.
Stig

Here's a picture of the bolts I am talking about that holds the casing or cover for the exhaust muffler:
https://imgur.com/a/CL1sYmr
The first one is more intact but the second one is kind of in bad shape.

Also another problem I run into is, I bought the 15/16 socket and it fits so great thanks CROSSBOLT and the others for the info. However, when I try to unscrew it counter-clockwise, the tire turns as well. Is there a specific way to unscrew the socket?

I was following this thread: https://www.kymcoforum.com/index.php?topic=11903.0
Should I first remove the axle nut first with the brake caliper on first, holding the break, and unscrew the nut, then remove the brake caliper?

Thanks

[Iahawk]

you just need to find a way to hold the rear wheel still while you loosen the axle bolt. I use a piece of 2x4 carefully placed between the wheel spokes and the swingarm...some will have a heavy friend sit on the bike...hold rear brake...there are a few ways to do it.

[CROSSBOLT]

Iowa Hawk beat me to it! I use the wood stick through the wheel to hold  it for unscrewing that nut. Your next challenge is getting the side plate off the back axle!

You are in the right place to find out how to do stuff! We got more bonafide techs here than any dealer. You will do just fine! Do what you are doing: ask questions, get answers, repeat. Take pictures when words fail. You are ahead of me on that one!

Now I understand what you meant about "foam washers!" Yes, there are rubbery grommets in there as a cushion. There should be also a little steel tube in all the washers to limit how much squeeze happens when each bolt is tightened. The grommets can be bought at Ace Hardware stores and Tractor Supply stores if in the US. The steel tubes can be made if similar sleeves not in the hardware store. The high temperature washers can be made from organic brake shoe material or a thick FEL-PRO head gasket. Many auto parts stores have thick high temp gasket material that can be doubled up to get whatever thickness needed.

[Seanny]

Iowa Hawk beat me to it! I use the wood stick through the wheel to hold  it for unscrewing that nut. Your next challenge is getting the side plate off the back axle!

You are in the right place to find out how to do stuff! We got more bonafide techs here than any dealer. You will do just fine! Do what you are doing: ask questions, get answers, repeat. Take pictures when words fail. You are ahead of me on that one!

Now I understand what you meant about "foam washers!" Yes, there are rubbery grommets in there as a cushion. There should be also a little steel tube in all the washers to limit how much squeeze happens when each bolt is tightened. The grommets can be bought at Ace Hardware stores and Tractor Supply stores if in the US. The steel tubes can be made if similar sleeves not in the hardware store. The high temperature washers can be made from organic brake shoe material or a thick FEL-PRO head gasket. Many auto parts stores have thick high temp gasket material that can be doubled up to get whatever thickness needed.

Thanks Iahawk and CROSSBOLT for the suggestions. I was able to get the wheel off finally! Now I just have to bring it to a shop and have them change it and balance it and then I'll have to reassemble everything back. Hopefully I have all the parts, bolts, and screws to do so. The hardest part I think is the side plate and the suspension. The side plate is really stiff to pull out and the suspension its just tough to squeeze my hand and tools to unscrew the bolt out.

Btw I also don't see this part when I pull the nut and side plate off: https://www.kymcoforum.com/index.php?action=dlattach;topic=11903.0;attach=17742;image
Maybe it's still sticked on the side plate but I am not sure.

Also when I reassemble everything back, is it recommended to put some anti-seize lubricant on the bolts for better disassembly in the future and also for preventing galling and corrosion?

[CROSSBOLT]

Btw I also don't see this part when I pull the nut and side plate off: https://www.kymcoforum.com/index.php?action=dlattach;topic=11903.0;attach=17742;image
Maybe it's still sticked on the side plate but I am not sure.

Yup! Still in the grease seal of the bearing in that sideplate! Use a little "antiseize" on the axle splines and shaft and that plate will come off easier next time!

[Seanny]

Btw I also don't see this part when I pull the nut and side plate off: https://www.kymcoforum.com/index.php?action=dlattach;topic=11903.0;attach=17742;image
Maybe it's still sticked on the side plate but I am not sure.

Yup! Still in the grease seal of the bearing in that sideplate! Use a little "antiseize" on the axle splines and shaft and that plate will come off easier next time!

Thanks
So I just reassembled everything back but when I was reassembling I accidentally squeezed the rear brake. I was thinking of using the brake to hold the wheel and screw the axle nut back but I forgot I haven't put the brake caliper back. I tried to ply the caliper back open a bit and it does fit back into the disk but I am not sure if they are balanced at all. When I spin the wheel with my hand I do hear a bit of scratching sounds.

Is there a way to test and ensure that everything is working fine? Should I readjust the brake after I accidentally squeezed the brake?

Thanks

[Ruffus]

@Seanny,
IF, when you had your caliper off and squeezed the brake handle, your brake-pads were IN  your caliper, you need not to worry. If you had them out and activated your brake, then piston and rubberseal has to be checked.
Scratching sound: brake discs get "wavy" by time, from heat and other influx. If this scratching is not permanent, you should be good to go.

[Seanny]

@Seanny,
IF, when you had your caliper off and squeezed the brake handle, your brake-pads were IN  your caliper, you need not to worry. If you had them out and activated your brake, then piston and rubberseal has to be checked.
Scratching sound: brake discs get "wavy" by time, from heat and other influx. If this scratching is not permanent, you should be good to go.

Yes the brake pads are in the caliper the are just not mounted on the disc when I squeezed the brake. So its only when the brake pads are off the caliper and I accidentally squeezed the brake that I have to get the brakes checked? Good to know then I guess I am good to go woohoo thanks all!